Application Server Failover

You can deploy two Application Servers as part of one logical site. Database replication enables the Application Servers to synchronize user profiles, user groups, and meeting data. Profile recorded names are not replicated automically. Only one Application Server is active at any time. If the active server fails, you can activate the standby server and place the previously active server in standby mode. Each Application Server in a site is called a node.

If the site includes two hardware Media Servers, then one Media Server will be associated with each Application Server. If the site includes only one hardware Media Server, it is always associated with the active Application Server.

In a failover deployment, each Application Server is configured with two IP addresses-one for each of these interfaces:

eth0-Physical network interface

Assign the same shared hostname and IP address to eth0 on both Application Servers.

Anyone who tries to access the shared hostname or IP address will reach the active Application Server.

The eth0 interface is disabled on the standby Application Server.

eth0:0-Virtual network interface

Assign a unique hostname and IP address to eth0:0 on each Application Server.

Use the eth0:0 hostname or IP address to access an Application Server that is in standby mode.

The system uses the eth0:0 virtual network interface for database replication between the two nodes.

Note: The interface eth0 mentioned throughout this module actually refers to the physical Ethernet port 1 on the Application Server.

When a node is rebooted, interface eth0 is initially disabled. However, during startup of the Cisco Unified MeetingPlace application, the node checks for an active Application Server on the network by attempting to ping the eth0 IP address, which is identical on both nodes. If the ping is unsuccessful, the rebooted node enables the eth0 interface and becomes the active server.

Configure the Domain Name System (DNS) server for forward and reverse DNS lookup of all three hostname-IP address pairs. Verify by running the nslookuphostname and nslookupip-address commands.

Whether you configure Application Server failover before or after you install any Web Server(s) and your call-control devices (such as Cisco Unified Communications Manager), make sure that these devices identify the active Application Server by using the shared hostname and IP address of eth0.

Only the database and Apache Tomcat processes run on a standby server, which you will notice if you enter the operating status command on the standby server.

When you configure the Application Server for the Express Media Server, both the primary and secondary failover Express Media Servers must have the same licenses and port distribution for scheduled and ad-hoc meetings.

The time must be synchronized between the two Application Servers. This is required to resolve conflicts when the same piece of data is modified simultaneously in both Application Servers.

The Informix database runs on the same machine as the Application Server. Port 2008 is configured in the Application Servers for database replication purposes.

If the primary and failover Application Servers share a common set of Audio and Video Blades, you must add all the Audio Blades to both Applications Servers. Be sure to use exactly the same passwords and SNMP community names on the two systems or the failover mechanism will not work.

Verifying

Using the hostname or IP address of the virtual eth0:0 interface, sign in to the Administration Center of each node, and verify that the correct failover deployment mode (active or standby) appears at the top of the page.

Procedure

Install the second Application Server (Node 2), ensuring the following:

To reduce system downtime during this procedure, enter the Node 2 eth0:0 (or any valid and currently unused) IP address and hostname when you configure "Ethernet Port 1(device eth0)" on the Network Setup page.

This configuration is temporary; you will change the eth0 IP address and hostname to the correct value later in this procedure.

Verifying

Using the hostname or IP address of the virtual eth0:0 interface, sign in to the Administration Center of each node, and verify that the correct failover deployment mode (active or standby) appears at the top of the page.

Before You Begin

Determine the hostname or IP address of both of these virtual network interfaces:

eth0:0 of the active server

eth0:0 of the standby server

Procedure

Go to http://application-server/admin/.

Use the shared eth0 hostname or IP address, which always goes to the active Application Server.

Sign in as a System administrator.

Configure the active server.

Take note of any changes you make on pages or fields that are labeled as:

Copied

Server-specific

Partially replicated

The "copyConfigFiles" commands will include recorded name files as well.

If you made changes to any copied pages or parameters, then perform these steps:

Sign in to the CLI of the active server.

If you are signing in remotely, use the eth0 IP address or hostname.

Enter this command to compress and transfer the files from the active server to the standby server:

failoverUtil copyConfigFiles

Sign in to the CLI of the standby server.

If you are signing in remotely, use eth0:0 IP address or hostname.

Enter this command to decompress the transferred files and put them in the correct directories on the standby server:

failoverUtil restoreConfigFiles

If you made changes to any server-specific pages or parameters, then perform these steps.

Tip: If your workstation screen is large enough to accommodate two full web browser windows without overlapping, then you can simultaneously view the Administration Center for both the active and standby servers. This might help you configure the server-specific parameters to match between the active and standby servers.

Go to http://standby-eth0:0/admin/.

Use either the hostname or IP address of the virtual eth0:0 interface of the standby Application Server.

Sign in as a System administrator.

Verify that "Failover deployment. Standby server." appears at the top of the page.

Configure the server-specific parameters on the standby server.

What to Do Next

Perform the following from both Application Servers to replicate custom prompts and some configurations from the Primary application server to the Standby application server during a maintenance window or off-peak hours.

Log in to the CLI of the active server.

If you are logging in remotely, use the eth0 IP address or hostname.

Enter the following command to compress and transfer the files from the active server to the standby server:

failoverUtil copyConfigFiles

This will compress and copy over configuration files and user prompts to the remote server.

Log in to the CLI of the standby server.

If you are logging in remotely, use eth0:0 IP address or hostname.

Enter the following command to decompress the transferred files and put them in the correct directories on the standby server:

failoverUtil restoreConfigFiles

This action copies over custom prompts including customized system prompts and user name recordings. Without this action .wav files are not replicated to the standby server.

Verifying

Using the hostname or IP address of the virtual eth0:0 interface, sign in to the Administration Center of each node, and verify that the correct failover deployment mode (active or standby) appears at the top of the page.

Verifying

Using the hostname or IP address of the virtual eth0:0 interface, sign in to the Administration Center of each node, and verify that the correct failover deployment mode (active or standby) appears at the top of the page.